This invention relates generally to combustors for gas turbine engines and more particularly to joints that connect a combustor dome plate to the combustor liners.
A gas turbine engine includes a compressor that provides pressurized air to a combustor wherein the air is mixed with fuel and ignited for generating hot combustion gases. These gases flow downstream to one or more turbines that extract energy therefrom to power the compressor and provide useful work such as powering an aircraft in flight. Combustors used in aircraft engines typically include inner and outer combustor liners to protect surrounding engine structure from the intense heat generated by the combustion process. The combustor liners are cooled to meet life expectancy requirements by diverting a portion of the compressed air and causing it to flow over the surfaces of the liners.
Advanced aircraft gas turbine engine technology is driving combustors to be shorter in length, have higher performance levels over wider operating ranges, and produce lower emission levels. To achieve these goals, the so-called trapped vortex combustor has been proposed. A trapped vortex combustor has a non-linear cavity section located immediately downstream of an inlet dome. Fuel and air injected into the cavity, which is substantially rectangular in cross-section, form a trapped vortex for igniting and stabilizing a flame in the combustor. This arrangement has shown robust operability including stable burning over a range of fuel/air ratios, high performance, low emissions and high efficiency at very high fuel/air ratios.
A trapped vortex combustor generally includes a flat dome plate that is joined to the outer and inner liners. This typically results in some dome-to-liner joint structure being located forward of the dome plate. A number of radial fuel injectors are located upstream of the dome plate. The radial fuel injectors are preferably located parallel to and in close proximity with the dome plate so as to avoid auto-ignition of the fuel prior to reaching the combustion zone. This leaves little room for dome-to-liner joints, particularly at the outer liner. In addition, a lack of streamlining at the external comer of the dome-to-liner joint can cause an undesirable pressure loss in the air diverted from the combustor for cooling purposes. This can decrease the cooling efficiency to the combustor liners as well as turbine components.
One approach to alleviating interference between the dome-to-liner joints and the fuel injectors would be to scallop the liners to fit around the fuel injectors. However, because of the large number of radial fuel injectors usually employed, the mechanical integrity of the liners would be at risk. Sealing between the liners and the dome plate would also be very difficult. Another possible approach would be to form each fuel injector with a bend so that the fuel injectors would fit around the joints. A drawback to this approach is that assembly of the combustor would become more complicated. Each fuel injector would be first slid radially inward forward of the dome plate and then slid axially aft to engage the dome plate. This installation method would require longer holes in the case enclosing the combustor liners. Longer holes would weaken the case and create more opportunity to undesirably leak air. Furthermore, the overall length of the engine would be increased to accommodate the sliding installation of the fuel injectors.
Accordingly, there is a need for a streamlined dome-to-liner joint that has no structure forward of the dome plate.
The above-mentioned need is met by the present invention, which provides a joint for joining a dome plate to a combustor liner. The joint includes a first flange formed on the dome plate and a second flange formed on the liner. A mounting ring having a groove formed therein is provided such that the first flange is disposed in the groove and the second flange engages the mounting ring. A retainer is secured to the mounting ring and engages the second flange.
The present invention and its advantages over the prior art will become apparent upon reading the following detailed description and the appended claims with reference to the accompanying drawings.